Heat exchangers designed for cooling and heating gases at pressures less than 3 atmospheres are widely used and well suited to finned heat exchanger coils. Such heat exchangers are used, for example, to cool gases used to carry grains into or out of storage bins, grain elevators, and rail cars. If the gases are not at the proper temperature, molding can occur, as can other problems associated with temperature and pressure.
Traditionally, many finned heat exchanger coils and housings for such applications have been rectangular in cross section, and nearly all pressurized gas flows into and out of the housing through gas carrier lines that have a round cross section. Industry practice has been to build heat exchanger housings that have square-to-round transitions in order to direct gases from the round carrier lines into the rectangular exchanger housing body.
The square-to-round transitions traditionally used have a first end that is generally square or rectangular and a second end that is generally round. This square or rectangular end of the transition has four distinct sides, plus four corners, and fastens to the rectangular housing. These four sides usually gradually round off to a circle at the second end of the transition. This circular second end connects to the circular gas carrier line.
Unfortunately, these existing square-to-round transitions used in such heat exchanger systems are problematic because they suffer from a number of draw backs. In particular, the four flat areas must be sufficiently thick and strong enough to avoid deformation and deflection when under pressure. Alternatively the flat areas must be reinforced in order to maintain the shape of the transition member within proper tolerances. If these flat areas display two much deflection, undue stress is transferred to the corners of the transitions, which suffer metal fatigue and fail.
Not only are these square-to-round transitions troublesome due to the fact that they are prone to failure if not constructed of sufficiently strong materials, they are also relatively difficult to make due to the fact that multiple bends must be made and reinforcing strips must be installed. These bends can add cost to the manufacture of the transition members because they require additional labor, and the reinforcing strips add cost by requiring additional material as well as additional labor.
Therefore, a need exists for an improved heat exchanger housing and transition that overcomes the aforementioned problems associated with present housings and transitions.